Question

A safe falls from rest from the top of a 37 m high cliff
towardWiley Coyote, who is standing at the base. Wiley first
notices thesafe after it has fallen 12.6 m. The acceleration of
gravity is 9.8m/s2 . How long does he have to get out of the way?
Answer in unitsof s.

I thought I had the answer by doing the following:
x=xo + vot + .5 a t2
-37=-4.9 t2t = 2.747912009

-24.4=-4.9 t2
t = 2.231499907

and then subtracting the two to get.... .516412016 s
But the answer is put into an online system and it will not
takethis number as an answer.
Any help would be appreciated.